Граф коммитов

202 Коммитов

Автор SHA1 Сообщение Дата
David Howells 0837e49ab3 KEYS: Differentiate uses of rcu_dereference_key() and user_key_payload()
rcu_dereference_key() and user_key_payload() are currently being used in
two different, incompatible ways:

 (1) As a wrapper to rcu_dereference() - when only the RCU read lock used
     to protect the key.

 (2) As a wrapper to rcu_dereference_protected() - when the key semaphor is
     used to protect the key and the may be being modified.

Fix this by splitting both of the key wrappers to produce:

 (1) RCU accessors for keys when caller has the key semaphore locked:

	dereference_key_locked()
	user_key_payload_locked()

 (2) RCU accessors for keys when caller holds the RCU read lock:

	dereference_key_rcu()
	user_key_payload_rcu()

This should fix following warning in the NFS idmapper

  ===============================
  [ INFO: suspicious RCU usage. ]
  4.10.0 #1 Tainted: G        W
  -------------------------------
  ./include/keys/user-type.h:53 suspicious rcu_dereference_protected() usage!
  other info that might help us debug this:
  rcu_scheduler_active = 2, debug_locks = 0
  1 lock held by mount.nfs/5987:
    #0:  (rcu_read_lock){......}, at: [<d000000002527abc>] nfs_idmap_get_key+0x15c/0x420 [nfsv4]
  stack backtrace:
  CPU: 1 PID: 5987 Comm: mount.nfs Tainted: G        W       4.10.0 #1
  Call Trace:
    dump_stack+0xe8/0x154 (unreliable)
    lockdep_rcu_suspicious+0x140/0x190
    nfs_idmap_get_key+0x380/0x420 [nfsv4]
    nfs_map_name_to_uid+0x2a0/0x3b0 [nfsv4]
    decode_getfattr_attrs+0xfac/0x16b0 [nfsv4]
    decode_getfattr_generic.constprop.106+0xbc/0x150 [nfsv4]
    nfs4_xdr_dec_lookup_root+0xac/0xb0 [nfsv4]
    rpcauth_unwrap_resp+0xe8/0x140 [sunrpc]
    call_decode+0x29c/0x910 [sunrpc]
    __rpc_execute+0x140/0x8f0 [sunrpc]
    rpc_run_task+0x170/0x200 [sunrpc]
    nfs4_call_sync_sequence+0x68/0xa0 [nfsv4]
    _nfs4_lookup_root.isra.44+0xd0/0xf0 [nfsv4]
    nfs4_lookup_root+0xe0/0x350 [nfsv4]
    nfs4_lookup_root_sec+0x70/0xa0 [nfsv4]
    nfs4_find_root_sec+0xc4/0x100 [nfsv4]
    nfs4_proc_get_rootfh+0x5c/0xf0 [nfsv4]
    nfs4_get_rootfh+0x6c/0x190 [nfsv4]
    nfs4_server_common_setup+0xc4/0x260 [nfsv4]
    nfs4_create_server+0x278/0x3c0 [nfsv4]
    nfs4_remote_mount+0x50/0xb0 [nfsv4]
    mount_fs+0x74/0x210
    vfs_kern_mount+0x78/0x220
    nfs_do_root_mount+0xb0/0x140 [nfsv4]
    nfs4_try_mount+0x60/0x100 [nfsv4]
    nfs_fs_mount+0x5ec/0xda0 [nfs]
    mount_fs+0x74/0x210
    vfs_kern_mount+0x78/0x220
    do_mount+0x254/0xf70
    SyS_mount+0x94/0x100
    system_call+0x38/0xe0

Reported-by: Jan Stancek <jstancek@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Tested-by: Jan Stancek <jstancek@redhat.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
2017-03-02 10:09:00 +11:00
Linus Torvalds 42e1b14b6e Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull locking updates from Ingo Molnar:
 "The main changes in this cycle were:

   - Implement wraparound-safe refcount_t and kref_t types based on
     generic atomic primitives (Peter Zijlstra)

   - Improve and fix the ww_mutex code (Nicolai Hähnle)

   - Add self-tests to the ww_mutex code (Chris Wilson)

   - Optimize percpu-rwsems with the 'rcuwait' mechanism (Davidlohr
     Bueso)

   - Micro-optimize the current-task logic all around the core kernel
     (Davidlohr Bueso)

   - Tidy up after recent optimizations: remove stale code and APIs,
     clean up the code (Waiman Long)

   - ... plus misc fixes, updates and cleanups"

* 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (50 commits)
  fork: Fix task_struct alignment
  locking/spinlock/debug: Remove spinlock lockup detection code
  lockdep: Fix incorrect condition to print bug msgs for MAX_LOCKDEP_CHAIN_HLOCKS
  lkdtm: Convert to refcount_t testing
  kref: Implement 'struct kref' using refcount_t
  refcount_t: Introduce a special purpose refcount type
  sched/wake_q: Clarify queue reinit comment
  sched/wait, rcuwait: Fix typo in comment
  locking/mutex: Fix lockdep_assert_held() fail
  locking/rtmutex: Flip unlikely() branch to likely() in __rt_mutex_slowlock()
  locking/rwsem: Reinit wake_q after use
  locking/rwsem: Remove unnecessary atomic_long_t casts
  jump_labels: Move header guard #endif down where it belongs
  locking/atomic, kref: Implement kref_put_lock()
  locking/ww_mutex: Turn off __must_check for now
  locking/atomic, kref: Avoid more abuse
  locking/atomic, kref: Use kref_get_unless_zero() more
  locking/atomic, kref: Kill kref_sub()
  locking/atomic, kref: Add kref_read()
  locking/atomic, kref: Add KREF_INIT()
  ...
2017-02-20 13:23:30 -08:00
Ondrej Kozina f5b0cba8f2 dm crypt: replace RCU read-side section with rwsem
The lockdep splat below hints at a bug in RCU usage in dm-crypt that
was introduced with commit c538f6ec9f ("dm crypt: add ability to use
keys from the kernel key retention service").  The kernel keyring
function user_key_payload() is in fact a wrapper for
rcu_dereference_protected() which must not be called with only
rcu_read_lock() section mark.

Unfortunately the kernel keyring subsystem doesn't currently provide
an interface that allows the use of an RCU read-side section.  So for
now we must drop RCU in favour of rwsem until a proper function is
made available in the kernel keyring subsystem.

===============================
[ INFO: suspicious RCU usage. ]
4.10.0-rc5 #2 Not tainted
-------------------------------
./include/keys/user-type.h:53 suspicious rcu_dereference_protected() usage!
other info that might help us debug this:
rcu_scheduler_active = 2, debug_locks = 1
2 locks held by cryptsetup/6464:
 #0:  (&md->type_lock){+.+.+.}, at: [<ffffffffa02472a2>] dm_lock_md_type+0x12/0x20 [dm_mod]
 #1:  (rcu_read_lock){......}, at: [<ffffffffa02822f8>] crypt_set_key+0x1d8/0x4b0 [dm_crypt]
stack backtrace:
CPU: 1 PID: 6464 Comm: cryptsetup Not tainted 4.10.0-rc5 #2
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.9.1-1.fc24 04/01/2014
Call Trace:
 dump_stack+0x67/0x92
 lockdep_rcu_suspicious+0xc5/0x100
 crypt_set_key+0x351/0x4b0 [dm_crypt]
 ? crypt_set_key+0x1d8/0x4b0 [dm_crypt]
 crypt_ctr+0x341/0xa53 [dm_crypt]
 dm_table_add_target+0x147/0x330 [dm_mod]
 table_load+0x111/0x350 [dm_mod]
 ? retrieve_status+0x1c0/0x1c0 [dm_mod]
 ctl_ioctl+0x1f5/0x510 [dm_mod]
 dm_ctl_ioctl+0xe/0x20 [dm_mod]
 do_vfs_ioctl+0x8e/0x690
 ? ____fput+0x9/0x10
 ? task_work_run+0x7e/0xa0
 ? trace_hardirqs_on_caller+0x122/0x1b0
 SyS_ioctl+0x3c/0x70
 entry_SYSCALL_64_fastpath+0x18/0xad
RIP: 0033:0x7f392c9a4ec7
RSP: 002b:00007ffef6383378 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007ffef63830a0 RCX: 00007f392c9a4ec7
RDX: 000000000124fcc0 RSI: 00000000c138fd09 RDI: 0000000000000005
RBP: 00007ffef6383090 R08: 00000000ffffffff R09: 00000000012482b0
R10: 2a28205d34383336 R11: 0000000000000246 R12: 00007f392d803a08
R13: 00007ffef63831e0 R14: 0000000000000000 R15: 00007f392d803a0b

Fixes: c538f6ec9f ("dm crypt: add ability to use keys from the kernel key retention service")
Reported-by: Milan Broz <mbroz@redhat.com>
Signed-off-by: Ondrej Kozina <okozina@redhat.com>
Reviewed-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2017-02-03 10:26:14 -05:00
Davidlohr Bueso 642fa448ae sched/core: Remove set_task_state()
This is a nasty interface and setting the state of a foreign task must
not be done. As of the following commit:

  be628be095 ("bcache: Make gc wakeup sane, remove set_task_state()")

... everyone in the kernel calls set_task_state() with current, allowing
the helper to be removed.

However, as the comment indicates, it is still around for those archs
where computing current is more expensive than using a pointer, at least
in theory. An important arch that is affected is arm64, however this has
been addressed now [1] and performance is up to par making no difference
with either calls.

Of all the callers, if any, it's the locking bits that would care most
about this -- ie: we end up passing a tsk pointer to a lot of the lock
slowpath, and setting ->state on that. The following numbers are based
on two tests: a custom ad-hoc microbenchmark that just measures
latencies (for ~65 million calls) between get_task_state() vs
get_current_state().

Secondly for a higher overview, an unlink microbenchmark was used,
which pounds on a single file with open, close,unlink combos with
increasing thread counts (up to 4x ncpus). While the workload is quite
unrealistic, it does contend a lot on the inode mutex or now rwsem.

[1] https://lkml.kernel.org/r/1483468021-8237-1-git-send-email-mark.rutland@arm.com

== 1. x86-64 ==

Avg runtime set_task_state():    601 msecs
Avg runtime set_current_state(): 552 msecs

                                            vanilla                 dirty
Hmean    unlink1-processes-2      36089.26 (  0.00%)    38977.33 (  8.00%)
Hmean    unlink1-processes-5      28555.01 (  0.00%)    29832.55 (  4.28%)
Hmean    unlink1-processes-8      37323.75 (  0.00%)    44974.57 ( 20.50%)
Hmean    unlink1-processes-12     43571.88 (  0.00%)    44283.01 (  1.63%)
Hmean    unlink1-processes-21     34431.52 (  0.00%)    38284.45 ( 11.19%)
Hmean    unlink1-processes-30     34813.26 (  0.00%)    37975.17 (  9.08%)
Hmean    unlink1-processes-48     37048.90 (  0.00%)    39862.78 (  7.59%)
Hmean    unlink1-processes-79     35630.01 (  0.00%)    36855.30 (  3.44%)
Hmean    unlink1-processes-110    36115.85 (  0.00%)    39843.91 ( 10.32%)
Hmean    unlink1-processes-141    32546.96 (  0.00%)    35418.52 (  8.82%)
Hmean    unlink1-processes-172    34674.79 (  0.00%)    36899.21 (  6.42%)
Hmean    unlink1-processes-203    37303.11 (  0.00%)    36393.04 ( -2.44%)
Hmean    unlink1-processes-224    35712.13 (  0.00%)    36685.96 (  2.73%)

== 2. ppc64le ==

Avg runtime set_task_state():  938 msecs
Avg runtime set_current_state: 940 msecs

                                            vanilla                 dirty
Hmean    unlink1-processes-2      19269.19 (  0.00%)    30704.50 ( 59.35%)
Hmean    unlink1-processes-5      20106.15 (  0.00%)    21804.15 (  8.45%)
Hmean    unlink1-processes-8      17496.97 (  0.00%)    17243.28 ( -1.45%)
Hmean    unlink1-processes-12     14224.15 (  0.00%)    17240.21 ( 21.20%)
Hmean    unlink1-processes-21     14155.66 (  0.00%)    15681.23 ( 10.78%)
Hmean    unlink1-processes-30     14450.70 (  0.00%)    15995.83 ( 10.69%)
Hmean    unlink1-processes-48     16945.57 (  0.00%)    16370.42 ( -3.39%)
Hmean    unlink1-processes-79     15788.39 (  0.00%)    14639.27 ( -7.28%)
Hmean    unlink1-processes-110    14268.48 (  0.00%)    14377.40 (  0.76%)
Hmean    unlink1-processes-141    14023.65 (  0.00%)    16271.69 ( 16.03%)
Hmean    unlink1-processes-172    13417.62 (  0.00%)    16067.55 ( 19.75%)
Hmean    unlink1-processes-203    15293.08 (  0.00%)    15440.40 (  0.96%)
Hmean    unlink1-processes-234    13719.32 (  0.00%)    16190.74 ( 18.01%)
Hmean    unlink1-processes-265    16400.97 (  0.00%)    16115.22 ( -1.74%)
Hmean    unlink1-processes-296    14388.60 (  0.00%)    16216.13 ( 12.70%)
Hmean    unlink1-processes-320    15771.85 (  0.00%)    15905.96 (  0.85%)

x86-64 (known to be fast for get_current()/this_cpu_read_stable() caching)
and ppc64 (with paca) show similar improvements in the unlink microbenches.
The small delta for ppc64 (2ms), does not represent the gains on the unlink
runs. In the case of x86, there was a decent amount of variation in the
latency runs, but always within a 20 to 50ms increase), ppc was more constant.

Signed-off-by: Davidlohr Bueso <dbueso@suse.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: dave@stgolabs.net
Cc: mark.rutland@arm.com
Link: http://lkml.kernel.org/r/1483479794-14013-5-git-send-email-dave@stgolabs.net
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2017-01-14 11:14:16 +01:00
Linus Torvalds 775a2e29c3 . various fixes and improvements to request-based DM and DM multipath
. some locking improvements in DM bufio
 
 . add Kconfig option to disable the DM block manager's extra locking
   which mainly serves as a developer tool
 
 . a few bug fixes to DM's persistent-data
 
 . a couple changes to prepare for multipage biovec support in the block
   layer
 
 . various improvements and cleanups in the DM core, DM cache, DM raid
   and DM crypt
 
 . add ability to have DM crypt use keys from the kernel key retention
   service
 
 . add a new "error_writes" feature to the DM flakey target, reads are
   left unchanged in this mode
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Merge tag 'dm-4.10-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper updates from Mike Snitzer:

 - various fixes and improvements to request-based DM and DM multipath

 - some locking improvements in DM bufio

 - add Kconfig option to disable the DM block manager's extra locking
   which mainly serves as a developer tool

 - a few bug fixes to DM's persistent-data

 - a couple changes to prepare for multipage biovec support in the block
   layer

 - various improvements and cleanups in the DM core, DM cache, DM raid
   and DM crypt

 - add ability to have DM crypt use keys from the kernel key retention
   service

 - add a new "error_writes" feature to the DM flakey target, reads are
   left unchanged in this mode

* tag 'dm-4.10-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: (40 commits)
  dm flakey: introduce "error_writes" feature
  dm cache policy smq: use hash_32() instead of hash_32_generic()
  dm crypt: reject key strings containing whitespace chars
  dm space map: always set ev if sm_ll_mutate() succeeds
  dm space map metadata: skip useless memcpy in metadata_ll_init_index()
  dm space map metadata: fix 'struct sm_metadata' leak on failed create
  Documentation: dm raid: define data_offset status field
  dm raid: fix discard support regression
  dm raid: don't allow "write behind" with raid4/5/6
  dm mpath: use hw_handler_params if attached hw_handler is same as requested
  dm crypt: add ability to use keys from the kernel key retention service
  dm array: remove a dead assignment in populate_ablock_with_values()
  dm ioctl: use offsetof() instead of open-coding it
  dm rq: simplify use_blk_mq initialization
  dm: use blk_set_queue_dying() in __dm_destroy()
  dm bufio: drop the lock when doing GFP_NOIO allocation
  dm bufio: don't take the lock in dm_bufio_shrink_count
  dm bufio: avoid sleeping while holding the dm_bufio lock
  dm table: simplify dm_table_determine_type()
  dm table: an 'all_blk_mq' table must be loaded for a blk-mq DM device
  ...
2016-12-14 11:01:00 -08:00
Ondrej Kozina 027c431ccf dm crypt: reject key strings containing whitespace chars
Unfortunately key_string may theoretically contain whitespace even after
it's processed by dm_split_args().  The reason for this is DM core
supports escaping of almost all chars including any whitespace.

If userspace passes a key to the kernel in format ":32:logon:my_prefix:my\ key"
dm-crypt will look up key "my_prefix:my key" in kernel keyring service.
So far everything's fine.

Unfortunately if userspace later calls DM_TABLE_STATUS ioctl, it will not
receive back expected ":32:logon:my_prefix:my\ key" but the unescaped version
instead.  Also userpace (most notably cryptsetup) is not ready to parse
single target argument containing (even escaped) whitespace chars and any
whitespace is simply taken as delimiter of another argument.

This effect is mitigated by the fact libdevmapper curently performs
double escaping of '\' char.  Any user input in format "x\ x" is
transformed into "x\\ x" before being passed to the kernel.  Nonetheless
dm-crypt may be used without libdevmapper.  Therefore the near-term
solution to this is to reject any key string containing whitespace.

Signed-off-by: Ondrej Kozina <okozina@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-12-08 14:13:16 -05:00
Ondrej Kozina c538f6ec9f dm crypt: add ability to use keys from the kernel key retention service
The kernel key service is a generic way to store keys for the use of
other subsystems. Currently there is no way to use kernel keys in dm-crypt.
This patch aims to fix that. Instead of key userspace may pass a key
description with preceding ':'. So message that constructs encryption
mapping now looks like this:

  <cipher> [<key>|:<key_string>] <iv_offset> <dev_path> <start> [<#opt_params> <opt_params>]

where <key_string> is in format: <key_size>:<key_type>:<key_description>

Currently we only support two elementary key types: 'user' and 'logon'.
Keys may be loaded in dm-crypt either via <key_string> or using
classical method and pass the key in hex representation directly.

dm-crypt device initialised with a key passed in hex representation may be
replaced with key passed in key_string format and vice versa.

(Based on original work by Andrey Ryabinin)

Signed-off-by: Ondrej Kozina <okozina@redhat.com>
Reviewed-by: David Howells <dhowells@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-12-08 14:13:09 -05:00
Julia Lawall 1b1b58f54f dm crypt: constify crypt_iv_operations structures
The crypt_iv_operations are never modified, so declare them
as const.

Done with the help of Coccinelle.

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-11-21 09:52:06 -05:00
Mikulas Patocka 671ea6b457 dm crypt: rename crypt_setkey_allcpus to crypt_setkey
In the past, dm-crypt used per-cpu crypto context. This has been removed
in the kernel 3.15 and the crypto context is shared between all cpus. This
patch renames the function crypt_setkey_allcpus to crypt_setkey, because
there is really no activity that is done for all cpus.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-11-21 09:52:00 -05:00
Ondrej Kozina 265e9098ba dm crypt: mark key as invalid until properly loaded
In crypt_set_key(), if a failure occurs while replacing the old key
(e.g. tfm->setkey() fails) the key must not have DM_CRYPT_KEY_VALID flag
set.  Otherwise, the crypto layer would have an invalid key that still
has DM_CRYPT_KEY_VALID flag set.

Cc: stable@vger.kernel.org
Signed-off-by: Ondrej Kozina <okozina@redhat.com>
Reviewed-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-11-21 09:51:59 -05:00
Ming Lei 0dae7fe597 dm crypt: use bio_add_page()
Use bio_add_page(), the standard interface for adding a page to a bio,
rather than open-coding the same.

It should be noted that the 'clone' bio that is allocated using
bio_alloc_bioset(), in crypt_alloc_buffer(), does _not_ set the
bio's BIO_CLONED flag.  As such, bio_add_page()'s early return for true
bio clones (those with BIO_CLONED set) isn't applicable.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-11-21 09:51:58 -05:00
Christoph Hellwig ef295ecf09 block: better op and flags encoding
Now that we don't need the common flags to overflow outside the range
of a 32-bit type we can encode them the same way for both the bio and
request fields.  This in addition allows us to place the operation
first (and make some room for more ops while we're at it) and to
stop having to shift around the operation values.

In addition this allows passing around only one value in the block layer
instead of two (and eventuall also in the file systems, but we can do
that later) and thus clean up a lot of code.

Last but not least this allows decreasing the size of the cmd_flags
field in struct request to 32-bits.  Various functions passing this
value could also be updated, but I'd like to avoid the churn for now.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-10-28 08:48:16 -06:00
Linus Torvalds 48915c2cbc . various fixes and cleanups for request-based DM core
. add support for delaying the requeue of requests; used by DM multipath
   when all paths have failed and 'queue_if_no_path' is enabled
 
 . DM cache improvements to speedup the loading metadata and the writing
   of the hint array
 
 . fix potential for a dm-crypt crash on device teardown
 
 . remove dm_bufio_cond_resched() and just using cond_resched()
 
 . change DM multipath to return a reservation conflict error
   immediately; rather than failing the path and retrying (potentially
   indefinitely)
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Merge tag 'dm-4.9-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper updates from Mike Snitzer:

 - various fixes and cleanups for request-based DM core

 - add support for delaying the requeue of requests; used by DM
   multipath when all paths have failed and 'queue_if_no_path' is
   enabled

 - DM cache improvements to speedup the loading metadata and the writing
   of the hint array

 - fix potential for a dm-crypt crash on device teardown

 - remove dm_bufio_cond_resched() and just using cond_resched()

 - change DM multipath to return a reservation conflict error
   immediately; rather than failing the path and retrying (potentially
   indefinitely)

* tag 'dm-4.9-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: (24 commits)
  dm mpath: always return reservation conflict without failing over
  dm bufio: remove dm_bufio_cond_resched()
  dm crypt: fix crash on exit
  dm cache metadata: switch to using the new cursor api for loading metadata
  dm array: introduce cursor api
  dm btree: introduce cursor api
  dm cache policy smq: distribute entries to random levels when switching to smq
  dm cache: speed up writing of the hint array
  dm array: add dm_array_new()
  dm mpath: delay the requeue of blk-mq requests while all paths down
  dm mpath: use dm_mq_kick_requeue_list()
  dm rq: introduce dm_mq_kick_requeue_list()
  dm rq: reduce arguments passed to map_request() and dm_requeue_original_request()
  dm rq: add DM_MAPIO_DELAY_REQUEUE to delay requeue of blk-mq requests
  dm: convert wait loops to use autoremove_wake_function()
  dm: use signal_pending_state() in dm_wait_for_completion()
  dm: rename task state function arguments
  dm: add two lockdep_assert_held() statements
  dm rq: simplify dm_old_stop_queue()
  dm mpath: check if path's request_queue is dying in activate_path()
  ...
2016-10-09 17:16:18 -07:00
Linus Torvalds 513a4befae Merge branch 'for-4.9/block' of git://git.kernel.dk/linux-block
Pull block layer updates from Jens Axboe:
 "This is the main pull request for block layer changes in 4.9.

  As mentioned at the last merge window, I've changed things up and now
  do just one branch for core block layer changes, and driver changes.
  This avoids dependencies between the two branches. Outside of this
  main pull request, there are two topical branches coming as well.

  This pull request contains:

   - A set of fixes, and a conversion to blk-mq, of nbd. From Josef.

   - Set of fixes and updates for lightnvm from Matias, Simon, and Arnd.
     Followup dependency fix from Geert.

   - General fixes from Bart, Baoyou, Guoqing, and Linus W.

   - CFQ async write starvation fix from Glauber.

   - Add supprot for delayed kick of the requeue list, from Mike.

   - Pull out the scalable bitmap code from blk-mq-tag.c and make it
     generally available under the name of sbitmap. Only blk-mq-tag uses
     it for now, but the blk-mq scheduling bits will use it as well.
     From Omar.

   - bdev thaw error progagation from Pierre.

   - Improve the blk polling statistics, and allow the user to clear
     them. From Stephen.

   - Set of minor cleanups from Christoph in block/blk-mq.

   - Set of cleanups and optimizations from me for block/blk-mq.

   - Various nvme/nvmet/nvmeof fixes from the various folks"

* 'for-4.9/block' of git://git.kernel.dk/linux-block: (54 commits)
  fs/block_dev.c: return the right error in thaw_bdev()
  nvme: Pass pointers, not dma addresses, to nvme_get/set_features()
  nvme/scsi: Remove power management support
  nvmet: Make dsm number of ranges zero based
  nvmet: Use direct IO for writes
  admin-cmd: Added smart-log command support.
  nvme-fabrics: Add host_traddr options field to host infrastructure
  nvme-fabrics: revise host transport option descriptions
  nvme-fabrics: rework nvmf_get_address() for variable options
  nbd: use BLK_MQ_F_BLOCKING
  blkcg: Annotate blkg_hint correctly
  cfq: fix starvation of asynchronous writes
  blk-mq: add flag for drivers wanting blocking ->queue_rq()
  blk-mq: remove non-blocking pass in blk_mq_map_request
  blk-mq: get rid of manual run of queue with __blk_mq_run_hw_queue()
  block: export bio_free_pages to other modules
  lightnvm: propagate device_add() error code
  lightnvm: expose device geometry through sysfs
  lightnvm: control life of nvm_dev in driver
  blk-mq: register device instead of disk
  ...
2016-10-07 14:42:05 -07:00
Rabin Vincent f659b10087 dm crypt: fix crash on exit
As the documentation for kthread_stop() says, "if threadfn() may call
do_exit() itself, the caller must ensure task_struct can't go away".
dm-crypt does not ensure this and therefore crashes when crypt_dtr()
calls kthread_stop().  The crash is trivially reproducible by adding a
delay before the call to kthread_stop() and just opening and closing a
dm-crypt device.

 general protection fault: 0000 [#1] PREEMPT SMP
 CPU: 0 PID: 533 Comm: cryptsetup Not tainted 4.8.0-rc7+ #7
 task: ffff88003bd0df40 task.stack: ffff8800375b4000
 RIP: 0010: kthread_stop+0x52/0x300
 Call Trace:
  crypt_dtr+0x77/0x120
  dm_table_destroy+0x6f/0x120
  __dm_destroy+0x130/0x250
  dm_destroy+0x13/0x20
  dev_remove+0xe6/0x120
  ? dev_suspend+0x250/0x250
  ctl_ioctl+0x1fc/0x530
  ? __lock_acquire+0x24f/0x1b10
  dm_ctl_ioctl+0x13/0x20
  do_vfs_ioctl+0x91/0x6a0
  ? ____fput+0xe/0x10
  ? entry_SYSCALL_64_fastpath+0x5/0xbd
  ? trace_hardirqs_on_caller+0x151/0x1e0
  SyS_ioctl+0x41/0x70
  entry_SYSCALL_64_fastpath+0x1f/0xbd

This problem was introduced by bcbd94ff48 ("dm crypt: fix a possible
hang due to race condition on exit").

Looking at the description of that patch (excerpted below), it seems
like the problem it addresses can be solved by just using
set_current_state instead of __set_current_state, since we obviously
need the memory barrier.

| dm crypt: fix a possible hang due to race condition on exit
|
| A kernel thread executes __set_current_state(TASK_INTERRUPTIBLE),
| __add_wait_queue, spin_unlock_irq and then tests kthread_should_stop().
| It is possible that the processor reorders memory accesses so that
| kthread_should_stop() is executed before __set_current_state().  If
| such reordering happens, there is a possible race on thread
| termination: [...]

So this patch just reverts the aforementioned patch and changes the
__set_current_state(TASK_INTERRUPTIBLE) to set_current_state(...).  This
fixes the crash and should also fix the potential hang.

Fixes: bcbd94ff48 ("dm crypt: fix a possible hang due to race condition on exit")
Cc: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org # v4.0+
Signed-off-by: Rabin Vincent <rabinv@axis.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-09-22 11:15:06 -04:00
Bart Van Assche 4382e33ad3 block, dm-crypt, btrfs: Introduce bio_flags()
Introduce the bio_flags() macro. Ensure that the second argument of
bio_set_op_attrs() only contains flags and no operation. This patch
does not change any functionality.

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Cc: Mike Christie <mchristi@redhat.com>
Cc: Chris Mason <clm@fb.com> (maintainer:BTRFS FILE SYSTEM)
Cc: Josef Bacik <jbacik@fb.com> (maintainer:BTRFS FILE SYSTEM)
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Damien Le Moal <damien.lemoal@hgst.com>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-09-14 08:48:27 -06:00
Eric Biggers 5d0be84ec0 dm crypt: fix free of bad values after tfm allocation failure
If crypt_alloc_tfms() had to allocate multiple tfms and it failed before
the last allocation, then it would call crypt_free_tfms() and could free
pointers from uninitialized memory -- due to the crypt_free_tfms() check
for non-zero cc->tfms[i].  Fix by allocating zeroed memory.

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2016-08-30 19:45:19 -04:00
Mikulas Patocka 4e870e948f dm crypt: fix error with too large bios
When dm-crypt processes writes, it allocates a new bio in
crypt_alloc_buffer().  The bio is allocated from a bio set and it can
have at most BIO_MAX_PAGES vector entries, however the incoming bio can be
larger (e.g. if it was allocated by bcache).  If the incoming bio is
larger, bio_alloc_bioset() fails and an error is returned.

To avoid the error, we test for a too large bio in the function
crypt_map() and use dm_accept_partial_bio() to split the bio.
dm_accept_partial_bio() trims the current bio to the desired size and
asks DM core to send another bio with the rest of the data.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org # v3.16+
2016-08-30 19:44:11 -04:00
Mikulas Patocka 0a83df6c8c dm crypt: increase mempool reserve to better support swapping
Increase mempool size from 16 to 64 entries.  This increase improves
swap on dm-crypt performance.

When swapping to dm-crypt, all available memory is temporarily exhausted
and dm-crypt can only use the mempool reserve.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-08-15 09:23:14 -04:00
Jens Axboe 1eff9d322a block: rename bio bi_rw to bi_opf
Since commit 63a4cc2486, bio->bi_rw contains flags in the lower
portion and the op code in the higher portions. This means that
old code that relies on manually setting bi_rw is most likely
going to be broken. Instead of letting that brokeness linger,
rename the member, to force old and out-of-tree code to break
at compile time instead of at runtime.

No intended functional changes in this commit.

Signed-off-by: Jens Axboe <axboe@fb.com>
2016-08-07 14:41:02 -06:00
Bart Van Assche 350b539328 dm crypt: Fix sparse complaints
Avoid that sparse complains about assigning a __le64 value to a u64
variable.  Remove the (u64) casts since these are superfluous.  This
patch does not change the behavior of the source code.

Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-07-01 10:53:21 -04:00
Mike Christie 28a8f0d317 block, drivers, fs: rename REQ_FLUSH to REQ_PREFLUSH
To avoid confusion between REQ_OP_FLUSH, which is handled by
request_fn drivers, and upper layers requesting the block layer
perform a flush sequence along with possibly a WRITE, this patch
renames REQ_FLUSH to REQ_PREFLUSH.

Signed-off-by: Mike Christie <mchristi@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-06-07 13:41:38 -06:00
Mike Christie e6047149db dm: use bio op accessors
Separate the op from the rq_flag_bits and have dm
set/get the bio using bio_set_op_attrs/bio_op.

Signed-off-by: Mike Christie <mchristi@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2016-06-07 13:41:38 -06:00
Linus Torvalds 70477371dc Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6
Pull crypto update from Herbert Xu:
 "Here is the crypto update for 4.6:

  API:
   - Convert remaining crypto_hash users to shash or ahash, also convert
     blkcipher/ablkcipher users to skcipher.
   - Remove crypto_hash interface.
   - Remove crypto_pcomp interface.
   - Add crypto engine for async cipher drivers.
   - Add akcipher documentation.
   - Add skcipher documentation.

  Algorithms:
   - Rename crypto/crc32 to avoid name clash with lib/crc32.
   - Fix bug in keywrap where we zero the wrong pointer.

  Drivers:
   - Support T5/M5, T7/M7 SPARC CPUs in n2 hwrng driver.
   - Add PIC32 hwrng driver.
   - Support BCM6368 in bcm63xx hwrng driver.
   - Pack structs for 32-bit compat users in qat.
   - Use crypto engine in omap-aes.
   - Add support for sama5d2x SoCs in atmel-sha.
   - Make atmel-sha available again.
   - Make sahara hashing available again.
   - Make ccp hashing available again.
   - Make sha1-mb available again.
   - Add support for multiple devices in ccp.
   - Improve DMA performance in caam.
   - Add hashing support to rockchip"

* 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6: (116 commits)
  crypto: qat - remove redundant arbiter configuration
  crypto: ux500 - fix checks of error code returned by devm_ioremap_resource()
  crypto: atmel - fix checks of error code returned by devm_ioremap_resource()
  crypto: qat - Change the definition of icp_qat_uof_regtype
  hwrng: exynos - use __maybe_unused to hide pm functions
  crypto: ccp - Add abstraction for device-specific calls
  crypto: ccp - CCP versioning support
  crypto: ccp - Support for multiple CCPs
  crypto: ccp - Remove check for x86 family and model
  crypto: ccp - memset request context to zero during import
  lib/mpi: use "static inline" instead of "extern inline"
  lib/mpi: avoid assembler warning
  hwrng: bcm63xx - fix non device tree compatibility
  crypto: testmgr - allow rfc3686 aes-ctr variants in fips mode.
  crypto: qat - The AE id should be less than the maximal AE number
  lib/mpi: Endianness fix
  crypto: rockchip - add hash support for crypto engine in rk3288
  crypto: xts - fix compile errors
  crypto: doc - add skcipher API documentation
  crypto: doc - update AEAD AD handling
  ...
2016-03-17 11:22:54 -07:00
Mike Snitzer 30187e1d48 dm: rename target's per_bio_data_size to per_io_data_size
Request-based DM will also make use of per_bio_data_size.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2016-02-22 22:34:37 -05:00
Herbert Xu bbdb23b5d6 dm crypt: Use skcipher and ahash
This patch replaces uses of ablkcipher with skcipher, and the long
obsolete hash interface with ahash.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2016-01-27 20:35:48 +08:00
Mikulas Patocka bcbd94ff48 dm crypt: fix a possible hang due to race condition on exit
A kernel thread executes __set_current_state(TASK_INTERRUPTIBLE),
__add_wait_queue, spin_unlock_irq and then tests kthread_should_stop().
It is possible that the processor reorders memory accesses so that
kthread_should_stop() is executed before __set_current_state().  If such
reordering happens, there is a possible race on thread termination:

CPU 0:
calls kthread_should_stop()
	it tests KTHREAD_SHOULD_STOP bit, returns false
CPU 1:
calls kthread_stop(cc->write_thread)
	sets the KTHREAD_SHOULD_STOP bit
	calls wake_up_process on the kernel thread, that sets the thread
	state to TASK_RUNNING
CPU 0:
sets __set_current_state(TASK_INTERRUPTIBLE)
spin_unlock_irq(&cc->write_thread_wait.lock)
schedule() - and the process is stuck and never terminates, because the
	state is TASK_INTERRUPTIBLE and wake_up_process on CPU 1 already
	terminated

Fix this race condition by using a new flag DM_CRYPT_EXIT_THREAD to
signal that the kernel thread should exit.  The flag is set and tested
while holding cc->write_thread_wait.lock, so there is no possibility of
racy access to the flag.

Also, remove the unnecessary set_task_state(current, TASK_RUNNING)
following the schedule() call.  When the process was woken up, its state
was already set to TASK_RUNNING.  Other kernel code also doesn't set the
state to TASK_RUNNING following schedule() (for example,
do_wait_for_common in completion.c doesn't do it).

Fixes: dc2676210c ("dm crypt: offload writes to thread")
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org # v4.0+
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-11-19 13:38:30 -05:00
Mel Gorman d0164adc89 mm, page_alloc: distinguish between being unable to sleep, unwilling to sleep and avoiding waking kswapd
__GFP_WAIT has been used to identify atomic context in callers that hold
spinlocks or are in interrupts.  They are expected to be high priority and
have access one of two watermarks lower than "min" which can be referred
to as the "atomic reserve".  __GFP_HIGH users get access to the first
lower watermark and can be called the "high priority reserve".

Over time, callers had a requirement to not block when fallback options
were available.  Some have abused __GFP_WAIT leading to a situation where
an optimisitic allocation with a fallback option can access atomic
reserves.

This patch uses __GFP_ATOMIC to identify callers that are truely atomic,
cannot sleep and have no alternative.  High priority users continue to use
__GFP_HIGH.  __GFP_DIRECT_RECLAIM identifies callers that can sleep and
are willing to enter direct reclaim.  __GFP_KSWAPD_RECLAIM to identify
callers that want to wake kswapd for background reclaim.  __GFP_WAIT is
redefined as a caller that is willing to enter direct reclaim and wake
kswapd for background reclaim.

This patch then converts a number of sites

o __GFP_ATOMIC is used by callers that are high priority and have memory
  pools for those requests. GFP_ATOMIC uses this flag.

o Callers that have a limited mempool to guarantee forward progress clear
  __GFP_DIRECT_RECLAIM but keep __GFP_KSWAPD_RECLAIM. bio allocations fall
  into this category where kswapd will still be woken but atomic reserves
  are not used as there is a one-entry mempool to guarantee progress.

o Callers that are checking if they are non-blocking should use the
  helper gfpflags_allow_blocking() where possible. This is because
  checking for __GFP_WAIT as was done historically now can trigger false
  positives. Some exceptions like dm-crypt.c exist where the code intent
  is clearer if __GFP_DIRECT_RECLAIM is used instead of the helper due to
  flag manipulations.

o Callers that built their own GFP flags instead of starting with GFP_KERNEL
  and friends now also need to specify __GFP_KSWAPD_RECLAIM.

The first key hazard to watch out for is callers that removed __GFP_WAIT
and was depending on access to atomic reserves for inconspicuous reasons.
In some cases it may be appropriate for them to use __GFP_HIGH.

The second key hazard is callers that assembled their own combination of
GFP flags instead of starting with something like GFP_KERNEL.  They may
now wish to specify __GFP_KSWAPD_RECLAIM.  It's almost certainly harmless
if it's missed in most cases as other activity will wake kswapd.

Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Vitaly Wool <vitalywool@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2015-11-06 17:50:42 -08:00
Julia Lawall 6f65985e26 dm: drop NULL test before kmem_cache_destroy() and mempool_destroy()
Remove DM's unneeded NULL tests before calling these destroy functions,
now that they check for NULL, thanks to these v4.3 commits:
3942d2991 ("mm/slab_common: allow NULL cache pointer in kmem_cache_destroy()")
4e3ca3e03 ("mm/mempool: allow NULL `pool' pointer in mempool_destroy()")

The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@ expression x; @@
-if (x != NULL)
  \(kmem_cache_destroy\|mempool_destroy\|dma_pool_destroy\)(x);
// </smpl>

Signed-off-by: Julia Lawall <Julia.Lawall@lip6.fr>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-10-31 19:06:00 -04:00
Mike Snitzer 586b286b11 dm crypt: constrain crypt device's max_segment_size to PAGE_SIZE
Setting the dm-crypt device's max_segment_size to PAGE_SIZE is an
unfortunate constraint that is required to avoid the potential for
exceeding dm-crypt's underlying device's max_segments limits -- due to
crypt_alloc_buffer() possibly allocating pages for the encryption bio
that are not as physically contiguous as the original bio.

It is interesting to note that this problem was already fixed back in
2007 via commit 91e106259 ("dm crypt: use bio_add_page").  But Linux 4.0
commit cf2f1abfb ("dm crypt: don't allocate pages for a partial
request") regressed dm-crypt back to _not_ using bio_add_page().  But
given dm-crypt's cpu parallelization changes all depend on commit
cf2f1abfb's abandoning of the more complex io fragments processing that
dm-crypt previously had we cannot easily go back to using
bio_add_page().

So all said the cleanest way to resolve this issue is to fix dm-crypt to
properly constrain the original bios entering dm-crypt so the encryption
bios that dm-crypt generates from the original bios are always
compatible with the underlying device's max_segments queue limits.

It should be noted that technically Linux 4.3 does _not_ need this fix
because of the block core's new late bio-splitting capability.  But, it
is reasoned, there is little to be gained by having the block core split
the encrypted bio that is composed of PAGE_SIZE segments.  That said, in
the future we may revert this change.

Fixes: cf2f1abfb ("dm crypt: don't allocate pages for a partial request")
Fixes: https://bugzilla.kernel.org/show_bug.cgi?id=104421
Suggested-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org # 4.0+
2015-09-14 12:04:24 -04:00
Linus Torvalds 1e1a4e8f43 Merge tag 'dm-4.3-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm
Pull device mapper update from Mike Snitzer:

 - a couple small cleanups in dm-cache, dm-verity, persistent-data's
   dm-btree, and DM core.

 - a 4.1-stable fix for dm-cache that fixes the leaking of deferred bio
   prison cells

 - a 4.2-stable fix that adds feature reporting for the dm-stats
   features added in 4.2

 - improve DM-snapshot to not invalidate the on-disk snapshot if
   snapshot device write overflow occurs; but a write overflow triggered
   through the origin device will still invalidate the snapshot.

 - optimize DM-thinp's async discard submission a bit now that late bio
   splitting has been included in block core.

 - switch DM-cache's SMQ policy lock from using a mutex to a spinlock;
   improves performance on very low latency devices (eg. NVMe SSD).

 - document DM RAID 4/5/6's discard support

[ I did not pull the slab changes, which weren't appropriate for this
  tree, and weren't obviously the right thing to do anyway.  At the very
  least they need some discussion and explanation before getting merged.

  Because not pulling the actual tagged commit but doing a partial pull
  instead, this merge commit thus also obviously is missing the git
  signature from the original tag ]

* tag 'dm-4.3-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm:
  dm cache: fix use after freeing migrations
  dm cache: small cleanups related to deferred prison cell cleanup
  dm cache: fix leaking of deferred bio prison cells
  dm raid: document RAID 4/5/6 discard support
  dm stats: report precise_timestamps and histogram in @stats_list output
  dm thin: optimize async discard submission
  dm snapshot: don't invalidate on-disk image on snapshot write overflow
  dm: remove unlikely() before IS_ERR()
  dm: do not override error code returned from dm_get_device()
  dm: test return value for DM_MAPIO_SUBMITTED
  dm verity: remove unused mempool
  dm cache: move wake_waker() from free_migrations() to where it is needed
  dm btree remove: remove unused function get_nr_entries()
  dm btree: remove unused "dm_block_t root" parameter in btree_split_sibling()
  dm cache policy smq: change the mutex to a spinlock
2015-09-02 16:35:26 -07:00
Kent Overstreet 8ae126660f block: kill merge_bvec_fn() completely
As generic_make_request() is now able to handle arbitrarily sized bios,
it's no longer necessary for each individual block driver to define its
own ->merge_bvec_fn() callback. Remove every invocation completely.

Cc: Jens Axboe <axboe@kernel.dk>
Cc: Lars Ellenberg <drbd-dev@lists.linbit.com>
Cc: drbd-user@lists.linbit.com
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Yehuda Sadeh <yehuda@inktank.com>
Cc: Sage Weil <sage@inktank.com>
Cc: Alex Elder <elder@kernel.org>
Cc: ceph-devel@vger.kernel.org
Cc: Alasdair Kergon <agk@redhat.com>
Cc: Mike Snitzer <snitzer@redhat.com>
Cc: dm-devel@redhat.com
Cc: Neil Brown <neilb@suse.de>
Cc: linux-raid@vger.kernel.org
Cc: Christoph Hellwig <hch@infradead.org>
Cc: "Martin K. Petersen" <martin.petersen@oracle.com>
Acked-by: NeilBrown <neilb@suse.de> (for the 'md' bits)
Acked-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
[dpark: also remove ->merge_bvec_fn() in dm-thin as well as
 dm-era-target, and resolve merge conflicts]
Signed-off-by: Dongsu Park <dpark@posteo.net>
Signed-off-by: Ming Lin <ming.l@ssi.samsung.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-08-13 12:31:57 -06:00
Vivek Goyal e80d1c805a dm: do not override error code returned from dm_get_device()
Some of the device mapper targets override the error code returned by
dm_get_device() and return either -EINVAL or -ENXIO.  There is nothing
gained by this override.  It is better to propagate the returned error
code unchanged to caller.

This work was motivated by hitting an issue where the underlying device
was busy but -EINVAL was being returned.  After this change we get
-EBUSY instead and it is easier to figure out the problem.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-08-12 11:32:21 -04:00
Sasha Levin 9b81c84235 block: don't access bio->bi_error after bio_put()
Commit 4246a0b6 ("block: add a bi_error field to struct bio") has added a few
dereferences of 'bio' after a call to bio_put(). This causes use-after-frees
such as:

[521120.719695] BUG: KASan: use after free in dio_bio_complete+0x2b3/0x320 at addr ffff880f36b38714
[521120.720638] Read of size 4 by task mount.ocfs2/9644
[521120.721212] =============================================================================
[521120.722056] BUG kmalloc-256 (Not tainted): kasan: bad access detected
[521120.722968] -----------------------------------------------------------------------------
[521120.722968]
[521120.723915] Disabling lock debugging due to kernel taint
[521120.724539] INFO: Slab 0xffffea003cdace00 objects=32 used=25 fp=0xffff880f36b38600 flags=0x46fffff80004080
[521120.726037] INFO: Object 0xffff880f36b38700 @offset=1792 fp=0xffff880f36b38800
[521120.726037]
[521120.726974] Bytes b4 ffff880f36b386f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
[521120.727898] Object ffff880f36b38700: 00 88 b3 36 0f 88 ff ff 00 00 d8 de 0b 88 ff ff  ...6............
[521120.728822] Object ffff880f36b38710: 02 00 00 f0 00 00 00 00 00 00 00 00 00 00 00 00  ................
[521120.729705] Object ffff880f36b38720: 01 00 00 00 00 00 00 00 00 00 00 00 01 00 00 00  ................
[521120.730623] Object ffff880f36b38730: 00 00 00 00 00 00 00 00 01 00 00 00 00 02 00 00  ................
[521120.731621] Object ffff880f36b38740: 00 02 00 00 01 00 00 00 d0 f7 87 ad ff ff ff ff  ................
[521120.732776] Object ffff880f36b38750: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
[521120.733640] Object ffff880f36b38760: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
[521120.734508] Object ffff880f36b38770: 01 00 03 00 01 00 00 00 88 87 b3 36 0f 88 ff ff  ...........6....
[521120.735385] Object ffff880f36b38780: 00 73 22 ad 02 88 ff ff 40 13 e0 3c 00 ea ff ff  .s".....@..<....
[521120.736667] Object ffff880f36b38790: 00 02 00 00 00 04 00 00 00 00 00 00 00 00 00 00  ................
[521120.737596] Object ffff880f36b387a0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
[521120.738524] Object ffff880f36b387b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
[521120.739388] Object ffff880f36b387c0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
[521120.740277] Object ffff880f36b387d0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
[521120.741187] Object ffff880f36b387e0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
[521120.742233] Object ffff880f36b387f0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
[521120.743229] CPU: 41 PID: 9644 Comm: mount.ocfs2 Tainted: G    B           4.2.0-rc6-next-20150810-sasha-00039-gf909086 #2420
[521120.744274]  ffff880f36b38000 ffff880d89c8f638 ffffffffb6e9ba8a ffff880101c0e5c0
[521120.745025]  ffff880d89c8f668 ffffffffad76a313 ffff880101c0e5c0 ffffea003cdace00
[521120.745908]  ffff880f36b38700 ffff880f36b38798 ffff880d89c8f690 ffffffffad772854
[521120.747063] Call Trace:
[521120.747520] dump_stack (lib/dump_stack.c:52)
[521120.748053] print_trailer (mm/slub.c:653)
[521120.748582] object_err (mm/slub.c:660)
[521120.749079] kasan_report_error (include/linux/kasan.h:20 mm/kasan/report.c:152 mm/kasan/report.c:194)
[521120.750834] __asan_report_load4_noabort (mm/kasan/report.c:250)
[521120.753580] dio_bio_complete (fs/direct-io.c:478)
[521120.755752] do_blockdev_direct_IO (fs/direct-io.c:494 fs/direct-io.c:1291)
[521120.759765] __blockdev_direct_IO (fs/direct-io.c:1322)
[521120.761658] blkdev_direct_IO (fs/block_dev.c:162)
[521120.762993] generic_file_read_iter (mm/filemap.c:1738)
[521120.767405] blkdev_read_iter (fs/block_dev.c:1649)
[521120.768556] __vfs_read (fs/read_write.c:423 fs/read_write.c:434)
[521120.772126] vfs_read (fs/read_write.c:454)
[521120.773118] SyS_pread64 (fs/read_write.c:607 fs/read_write.c:594)
[521120.776062] entry_SYSCALL_64_fastpath (arch/x86/entry/entry_64.S:186)
[521120.777375] Memory state around the buggy address:
[521120.778118]  ffff880f36b38600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[521120.779211]  ffff880f36b38680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[521120.780315] >ffff880f36b38700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[521120.781465]                          ^
[521120.782083]  ffff880f36b38780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
[521120.783717]  ffff880f36b38800: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
[521120.784818] ==================================================================

This patch fixes a few of those places that I caught while auditing the patch, but the
original patch should be audited further for more occurences of this issue since I'm
not too familiar with the code.

Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-08-11 11:34:32 -06:00
Christoph Hellwig 4246a0b63b block: add a bi_error field to struct bio
Currently we have two different ways to signal an I/O error on a BIO:

 (1) by clearing the BIO_UPTODATE flag
 (2) by returning a Linux errno value to the bi_end_io callback

The first one has the drawback of only communicating a single possible
error (-EIO), and the second one has the drawback of not beeing persistent
when bios are queued up, and are not passed along from child to parent
bio in the ever more popular chaining scenario.  Having both mechanisms
available has the additional drawback of utterly confusing driver authors
and introducing bugs where various I/O submitters only deal with one of
them, and the others have to add boilerplate code to deal with both kinds
of error returns.

So add a new bi_error field to store an errno value directly in struct
bio and remove the existing mechanisms to clean all this up.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Reviewed-by: NeilBrown <neilb@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
2015-07-29 08:55:15 -06:00
Milan Broz 54cea3f668 dm crypt: add comments to better describe crypto processing logic
A crypto driver can process requests synchronously or asynchronously
and can use an internal driver queue to backlog requests.
Add some comments to clarify internal logic and completion return codes.

Signed-off-by: Milan Broz <mbroz@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-29 14:19:02 -04:00
Rabin Vincent c0403ec0bb Revert "dm crypt: fix deadlock when async crypto algorithm returns -EBUSY"
This reverts Linux 4.1-rc1 commit 0618764cb2.

The problem which that commit attempts to fix actually lies in the
Freescale CAAM crypto driver not dm-crypt.

dm-crypt uses CRYPTO_TFM_REQ_MAY_BACKLOG.  This means the the crypto
driver should internally backlog requests which arrive when the queue is
full and process them later.  Until the crypto hw's queue becomes full,
the driver returns -EINPROGRESS.  When the crypto hw's queue if full,
the driver returns -EBUSY, and if CRYPTO_TFM_REQ_MAY_BACKLOG is set, is
expected to backlog the request and process it when the hardware has
queue space.  At the point when the driver takes the request from the
backlog and starts processing it, it calls the completion function with
a status of -EINPROGRESS.  The completion function is called (for a
second time, in the case of backlogged requests) with a status/err of 0
when a request is done.

Crypto drivers for hardware without hardware queueing use the helpers,
crypto_init_queue(), crypto_enqueue_request(), crypto_dequeue_request()
and crypto_get_backlog() helpers to implement this behaviour correctly,
while others implement this behaviour without these helpers (ccp, for
example).

dm-crypt (before the patch that needs reverting) uses this API
correctly.  It queues up as many requests as the hw queues will allow
(i.e. as long as it gets back -EINPROGRESS from the request function).
Then, when it sees at least one backlogged request (gets -EBUSY), it
waits till that backlogged request is handled (completion gets called
with -EINPROGRESS), and then continues.  The references to
af_alg_wait_for_completion() and af_alg_complete() in that commit's
commit message are irrelevant because those functions only handle one
request at a time, unlink dm-crypt.

The problem is that the Freescale CAAM driver, which that commit
describes as having being tested with, fails to implement the
backlogging behaviour correctly.  In cam_jr_enqueue(), if the hardware
queue is full, it simply returns -EBUSY without backlogging the request.
What the observed deadlock was is not described in the commit message
but it is obviously the wait_for_completion() in crypto_convert() where
dm-crypto would wait for the completion being called with -EINPROGRESS
in the case of backlogged requests.  This completion will never be
completed due to the bug in the CAAM driver.

Commit 0618764cb2 incorrectly made dm-crypt wait for every request,
even when the driver/hardware queues are not full, which means that
dm-crypt will never see -EBUSY.  This means that that commit will cause
a performance regression on all crypto drivers which implement the API
correctly.

Revert it.  Correct backlog handling should be implemented in the CAAM
driver instead.

Cc'ing stable purely because commit 0618764cb2 did.  If for some reason
a stable@ kernel did pick up commit 0618764cb2 it should get reverted.

Signed-off-by: Rabin Vincent <rabin.vincent@axis.com>
Reviewed-by: Horia Geanta <horia.geanta@freescale.com>
Cc: stable@vger.kernel.org
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-05-05 12:16:43 -04:00
Wei Yongjun 44c144f9c8 dm crypt: fix missing error code return from crypt_ctr error path
Fix to return a negative error code from crypt_ctr()'s optional
parameter processing error path.

Signed-off-by: Wei Yongjun <yongjun_wei@trendmicro.com.cn>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-16 22:00:50 -04:00
Ben Collins 0618764cb2 dm crypt: fix deadlock when async crypto algorithm returns -EBUSY
I suspect this doesn't show up for most anyone because software
algorithms typically don't have a sense of being too busy.  However,
when working with the Freescale CAAM driver it will return -EBUSY on
occasion under heavy -- which resulted in dm-crypt deadlock.

After checking the logic in some other drivers, the scheme for
crypt_convert() and it's callback, kcryptd_async_done(), were not
correctly laid out to properly handle -EBUSY or -EINPROGRESS.

Fix this by using the completion for both -EBUSY and -EINPROGRESS.  Now
crypt_convert()'s use of completion is comparable to
af_alg_wait_for_completion().  Similarly, kcryptd_async_done() follows
the pattern used in af_alg_complete().

Before this fix dm-crypt would lockup within 1-2 minutes running with
the CAAM driver.  Fix was regression tested against software algorithms
on PPC32 and x86_64, and things seem perfectly happy there as well.

Signed-off-by: Ben Collins <ben.c@servergy.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2015-04-15 12:10:26 -04:00
Mike Snitzer 5977907937 dm crypt: leverage immutable biovecs when decrypting on read
Commit 003b5c571 ("block: Convert drivers to immutable biovecs")
stopped short of changing dm-crypt to leverage the fact that the biovec
array of a bio will no longer be modified.

Switch to using bio_clone_fast() when cloning bios for decryption after
read.

Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-15 12:10:25 -04:00
Milan Broz e44f23b32d dm crypt: update URLs to new cryptsetup project page
Cryptsetup home page moved to GitLab.
Also remove link to abandonded Truecrypt page.

Signed-off-by: Milan Broz <gmazyland@gmail.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-04-15 12:10:24 -04:00
Mikulas Patocka b3c5fd3052 dm crypt: sort writes
Write requests are sorted in a red-black tree structure and are
submitted in the sorted order.

In theory the sorting should be performed by the underlying disk
scheduler, however, in practice the disk scheduler only accepts and
sorts a finite number of requests.  To allow the sorting of all
requests, dm-crypt needs to implement its own sorting.

The overhead associated with rbtree-based sorting is considered
negligible so it is not used conditionally.  Even on SSD sorting can be
beneficial since in-order request dispatch promotes lower latency IO
completion to the upper layers.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-02-16 11:11:15 -05:00
Mikulas Patocka 0f5d8e6ee7 dm crypt: add 'submit_from_crypt_cpus' option
Make it possible to disable offloading writes by setting the optional
'submit_from_crypt_cpus' table argument.

There are some situations where offloading write bios from the
encryption threads to a single thread degrades performance
significantly.

The default is to offload write bios to the same thread because it
benefits CFQ to have writes submitted using the same IO context.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-02-16 11:11:15 -05:00
Mikulas Patocka dc2676210c dm crypt: offload writes to thread
Submitting write bios directly in the encryption thread caused serious
performance degradation.  On a multiprocessor machine, encryption requests
finish in a different order than they were submitted.  Consequently, write
requests would be submitted in a different order and it could cause severe
performance degradation.

Move the submission of write requests to a separate thread so that the
requests can be sorted before submitting.  But this commit improves
dm-crypt performance even without having dm-crypt perform request
sorting (in particular it enables IO schedulers like CFQ to sort more
effectively).

Note: it is required that a previous commit ("dm crypt: don't allocate
pages for a partial request") be applied before applying this patch.
Otherwise, this commit could introduce a crash.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-02-16 11:11:14 -05:00
Mikulas Patocka 94f5e0243c dm crypt: remove unused io_pool and _crypt_io_pool
The previous commit ("dm crypt: don't allocate pages for a partial
request") stopped using the io_pool slab mempool and backing
_crypt_io_pool kmem cache.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-02-16 11:11:13 -05:00
Mikulas Patocka 7145c241a1 dm crypt: avoid deadlock in mempools
Fix a theoretical deadlock introduced in the previous commit ("dm crypt:
don't allocate pages for a partial request").

The function crypt_alloc_buffer may be called concurrently.  If we allocate
from the mempool concurrently, there is a possibility of deadlock.  For
example, if we have mempool of 256 pages, two processes, each wanting
256, pages allocate from the mempool concurrently, it may deadlock in a
situation where both processes have allocated 128 pages and the mempool
is exhausted.

To avoid such a scenario we allocate the pages under a mutex.  In order
to not degrade performance with excessive locking, we try non-blocking
allocations without a mutex first and if that fails, we fallback to a
blocking allocations with a mutex.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-02-16 11:11:13 -05:00
Mikulas Patocka cf2f1abfbd dm crypt: don't allocate pages for a partial request
Change crypt_alloc_buffer so that it only ever allocates pages for a
full request.  This is a prerequisite for the commit "dm crypt: offload
writes to thread".

This change simplifies the dm-crypt code at the expense of reduced
throughput in low memory conditions (where allocation for a partial
request is most useful).

Note: the next commit ("dm crypt: avoid deadlock in mempools") is needed
to fix a theoretical deadlock.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-02-16 11:11:12 -05:00
Mikulas Patocka f3396c58fd dm crypt: use unbound workqueue for request processing
Use unbound workqueue by default so that work is automatically balanced
between available CPUs.  The original behavior of encrypting using the
same cpu that IO was submitted on can still be enabled by setting the
optional 'same_cpu_crypt' table argument.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
2015-02-16 11:10:59 -05:00
Linus Torvalds 140dfc9299 - Significant DM thin-provisioning performance improvements to meet
performance requirements that were requested by the Gluster
   distributed filesystem.  Specifically, dm-thinp now takes care to
   aggregate IO that will be issued to the same thinp block before
   issuing IO to the underlying devices.  This really helps improve
   performance on HW RAID6 devices that have a writeback cache because it
   avoids RMW in the HW RAID controller.
 
 - Some stable fixes: fix leak in DM bufio if integrity profiles were
   enabled, use memzero_explicit in DM crypt to avoid any potential for
   information leak, and a DM cache fix to properly mark a cache block
   dirty if it was promoted to the cache via the overwrite optimization.
 
 - A few simple DM persistent data library fixes
 
 - DM cache multiqueue policy block promotion improvements.
 
 - DM cache discard improvements that take advantage of range
   (multiblock) discard support in the DM bio-prison.  This allows for
   much more efficient bulk discard processing (e.g. when mkfs.xfs
   discards the entire device).
 
 - Some small optimizations in DM core and RCU deference cleanups
 
 - DM core changes to suspend/resume code to introduce the new internal
   suspend/resume interface that the DM thin-pool target now uses to
   suspend/resume active thin devices when the thin-pool must
   suspend/resume.  This avoids forcing userspace to track all active
   thin volumes in a thin-pool when the thin-pool is suspended for the
   purposes of metadata or data space resize.
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Merge tag 'dm-3.19-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper updates from Mike Snitzer:

 - Significant DM thin-provisioning performance improvements to meet
   performance requirements that were requested by the Gluster
   distributed filesystem.

   Specifically, dm-thinp now takes care to aggregate IO that will be
   issued to the same thinp block before issuing IO to the underlying
   devices.  This really helps improve performance on HW RAID6 devices
   that have a writeback cache because it avoids RMW in the HW RAID
   controller.

 - Some stable fixes: fix leak in DM bufio if integrity profiles were
   enabled, use memzero_explicit in DM crypt to avoid any potential for
   information leak, and a DM cache fix to properly mark a cache block
   dirty if it was promoted to the cache via the overwrite optimization.

 - A few simple DM persistent data library fixes

 - DM cache multiqueue policy block promotion improvements.

 - DM cache discard improvements that take advantage of range
   (multiblock) discard support in the DM bio-prison.  This allows for
   much more efficient bulk discard processing (e.g.  when mkfs.xfs
   discards the entire device).

 - Some small optimizations in DM core and RCU deference cleanups

 - DM core changes to suspend/resume code to introduce the new internal
   suspend/resume interface that the DM thin-pool target now uses to
   suspend/resume active thin devices when the thin-pool must
   suspend/resume.

   This avoids forcing userspace to track all active thin volumes in a
   thin-pool when the thin-pool is suspended for the purposes of
   metadata or data space resize.

* tag 'dm-3.19-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: (49 commits)
  dm crypt: use memzero_explicit for on-stack buffer
  dm space map metadata: fix sm_bootstrap_get_count()
  dm space map metadata: fix sm_bootstrap_get_nr_blocks()
  dm bufio: fix memleak when using a dm_buffer's inline bio
  dm cache: fix spurious cell_defer when dealing with partial block at end of device
  dm cache: dirty flag was mistakenly being cleared when promoting via overwrite
  dm cache: only use overwrite optimisation for promotion when in writeback mode
  dm cache: discard block size must be a multiple of cache block size
  dm cache: fix a harmless race when working out if a block is discarded
  dm cache: when reloading a discard bitset allow for a different discard block size
  dm cache: fix some issues with the new discard range support
  dm array: if resizing the array is a noop set the new root to the old one
  dm: use rcu_dereference_protected instead of rcu_dereference
  dm thin: fix pool_io_hints to avoid looking at max_hw_sectors
  dm thin: suspend/resume active thin devices when reloading thin-pool
  dm: enhance internal suspend and resume interface
  dm thin: do not allow thin device activation while pool is suspended
  dm: add presuspend_undo hook to target_type
  dm: return earlier from dm_blk_ioctl if target doesn't implement .ioctl
  dm thin: remove stale 'trim' message in block comment above pool_message
  ...
2014-12-08 21:10:03 -08:00
Milan Broz 1a71d6ffe1 dm crypt: use memzero_explicit for on-stack buffer
Use memzero_explicit to cleanup sensitive data allocated on stack
to prevent the compiler from optimizing and removing memset() calls.

Signed-off-by: Milan Broz <gmazyland@gmail.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
2014-12-02 10:25:07 -05:00